NORTH AMERICAN EARLY TERTIARY BRYOZOA. 



793 



vox, elongated, elliptical, symmetrical, suspended on the lateral edge of the zoariuni ; 

 the oeciostome is terminal, very large, transverse, fastened to a small isolated tube, 

 and separated from the fascicles. 



-Diameter of the peristoine 0.10 mm. 



,, Distance between the fascicles.. _ 0.30 mm 



Measurements. .. ,,, . , ,. . , 



Width ot the fascicles 0.12 mm. 



Width of the branches 2.00 mm. 



\'<iri(tticms. The lamellar fascicles are often oblique 

 (fig. 3) ; the sixth tube, which composes them and which 

 is placed in the vicinity of the lateral edge, is often isolated. 



The ovicell is always placed laterally (fig. 1) ; its posi- 

 tion is hardly disarranged at the bifurcations (fig. 2), even 

 though this takes place at a very acute angle. It is remark- 

 able that the oeciostome should be joined to a tube, but this 

 tube does not belong to a fascicle, for it is always 

 isolated. 



The variation of the nature of the ovicells in species with 

 the Idnwnea form of growth is very great. This is a proof 

 of the poor method followed even to this day by the natural- 

 ists is the classification of the cyclostomatous bryozoa. 

 Idnwnea unrestricted is only a zoarial form common to a 

 great many families. 



Occurrence. Wilcoxian (Bashi formation): Woods 

 Bluff, Alabama (common). 



Cotypes.Crt.. No. 65264, U.S.N.M. 



Genus PROSTHENOECIA Canu, 1918. 



FIG. 255. Genus Prosthe- 

 noecia) Canu, 1918. 

 Two ovicelled zoaria of 

 Prosthenoecia (Reptotubig- 

 tra) latcralis, D'Orbigny, 

 1852, from the Lutetian of 

 France. 



1918. Prosthenoecia CANU, Les ovicelles des bryozoaires cyclostomes, Bulletin Society 

 g6ologique de France, ser. 4, vol. 16, p. 327. 



The ovicell is placed on the celluliferous face; the oeciostome is large and trans- 

 verse. 



Genotype. Prosthenoecia (Reptotubigera) lateraUs D'Orbigny, 1852. 

 Lutetian. 



Family HORNERIDAE Gregory, 1899. 



Anatomical bibliography. 18S8. WATERS, On some Ovicells of Cyclostoinatous Bryozoa, Journal 

 Linnean Society, London. Zoology, vol. 20, p. 275, pt. 14, figs. 1, 3, 4,7. 1003. WATERS, Bryozoa 

 from Franz-Joseph Land, pt. 2, Journal Linneau Society, London, Zoology, vol. 29, p. 168, pi. 

 20, figs. 1-6. 1904. WATERS, Expedition antarctic Beige, Bryozoa, p. 93, pi. 9, fig. 1. 1911. 

 HENNIG, Le conglouierat pleistocene a Pecten de 1'ile de Cockburn, Wissenshaftliche ergebuisse 

 der schwedisctien sudpolar expedition, vol. 3, p. 37, pi. 5, figs. 8-11. 1914. WATERS, Marine 

 Fauna British East Africa and Zanzibar Bryozoa, Cyclostomata, Proceedings Zoological 

 Society, London, p. 836. 



The ovicell is symmetrical, sacciform, subglobular. The oeciostome is lateral 

 and opens on the frontal. The zoarial walls are lamellose and squamous. They are 

 traversed by vacuoles. 



